DOUBLE IMMUNOSTAINING FOR P53 AND MOLECULAR CHAPERONE HSP72 73 IN GASTRIC-CARCINOMA/

Aims-To examine the relation between the expression of p53 protein and the chaperone heat shock protein (hsp)72/73 in a population at high r isk for gastric carcinoma, using single and double immunohistochemistr y, and to compare the expression of these two proteins with clinicopat hological features. Methods-Monoclonal antibodies were used to investi gate the expression of p53 protein and hsp72/73 in 46 human gastric ca rcinomas. A double immunohistochemical technique was used in cases tha t showed p53/hsp72/73 coexpression. Results-p53 immunoreactivity was p resent in 11 tumours (24%), and hsp72/73 immunostaining was observed i n 22 cases (48%). p53 expression was observed as nuclear staining in t umoral cells. hsp72/73 expression was demonstrated mainly as cytoplasm ic staining, but six tumours also showed focal weak nuclear staining. Seven cases showed p53 and hsp72/73 coexpression with immunoreactivity for both proteins in the same neoplastic cells, three of them with fo cal areas of nuclear coexpression. p53 expression was seen more freque ntly in cases that showed a high intensity (+++) of hsp72/73 staining. No significant association was observed between the expression of the two proteins and clinicopathological features. Conclusions-More than half of our cases may have some impairment in p53 protein growth suppr essive function, asa result of p53 gene alterations or complex formati on. The positive correlation between p53 expression and intensity of h sp72/73 supports the postulate of a p53 regulating function for the ch aperone hsp72/73. A high intensity of hsp72/73 immunohistochemical sta ining could be used as an indirect marker of p53 gene abnormalities.